1. Field of the Invention
The present invention relates generally to endless traction belts or tracks used in driving snowmobiles. In particular, the present invention relates to improved cleats made of a flexible, resilient, elastomeric material and which when installed on the track of the snowmobile will greatly improve the ability of the track of the snowmobile to lift the track and the snowmobile upon snow and carry the snowmobile over the snow without bogging down in light or deep snow. The invention further relates to such improved cleats which will even allow the snowmobile to plane upon a water surface such as a lake or other substantially deep body of water.
2. State of the Art
Snowmobiles are used extensively in snowy regions, not only for everyday use, but they are also used widely for recreational and emergency purposes. Snowmobiles are operated on a wide variety of terrain. They are used in hilly or mountainous regions as well as on flat land. They are operated on fresh snow, on trails conditioned for snowmobile riding, on hard packed snow, on the icy surfaces of streams, rivers, and lakes, and on hard snow packed or icy roads. Recently, recreational use of snowmobiles has even extended to running the snowmobile on the surface of an unfrozen body of water such as a lake. In the latter use, the snowmobile must be kept up to a substantial speed in substantially a linear motion to keep the snowmobile on top of the water. If the velocity of the snowmobile drops or if the snowmobile is turned in its direction of travel, the track is no longer able to support the snowmobile on the water, and the snowmobile sinks in the water.
Continuous drive tracks are conventionally used for engaging the snow covered surface, the icy surface or the surface of a body of water in order to provide the propulsion to move the snowmobile forward. When the snowmobile is being used on snow or ice covered surfaces, the drive track must provide proper traction to propel the snowmobile forward. When the snowmobile is being operated on a water surface, the speed and rotation of the track provides a minimal degree of lift which is used in combination with lift inherent in the forward speed of the snowmobile to keep the snowmobile afloat on top of the surface of the body of water. In order to provide proper traction on snow and ice, as well as for uphill downhill and other conditions in which snowmobiles are used, the design of the track is very important. Generally speaking, the traction belt or track has a width substantially equal to the seat portion at the rear of the snowmobile. The track is drivably suspended on the frame of the snowmobile and is generally positioned at the rear portion of the snowmobile, while a pair of steerable skis support the front end of the snowmobile.
An example of a conventional track for a snowmobile is shown in U.S. Pat. No. 3,623,780. The track is generally made of an elastomeric material, with a plurality of transversely mounted and longitudinally spaced, rigid, elongate drive cleats being secured or mounted on the outside of the track. The drive cleats, which are conventionally U-shaped in cross-section, provide traction with the terrain in order to propel the snowmobile in a forward direction. Braking of the snowmobile is also accomplished utilizing the track. In braking, the track is slowed or stopped, and the cleats on the track then dig into the snow or ice on the ground to slow and stop the snowmobile.
Although there are enumerable snowmobiles in use, all of which utilize tracks having some type traction means such as the cleats mentioned above, the drive systems comprising such tracts are not without problems which can be irritable and downright troublesome to the snowmobiler. When the snowmobile is bucking deep snow, attempting to climb hills, breaking a new trail through snow, or is being operated in numerous other modes involving high load conditions wherein traction is of great importance, the traction means, such as the cleats mentioned above, have a universal tendency to dig deeply into the snow and ultimately bog the snowmobile down in the snow. Heretofore, there has been no provision by which the track could be designed to provide necessary traction while at the same time providing lift for the track and the snowmobile to keep the track from digging deep into the snow and bogging the snowmobile down.
In U.S. Pat. No. 4,175,627, there is disclosed a lightweight propulsion system for a power driven ski device in which a continuous drive track is provided. The drive track is relatively small and lightweight, with the drive track having a width which is approximately only that of a ski. The drive track comprises resilient cleats which extent transversely across the width of the track and are spaced along the circumferential length of the track. The cleats comprise substantially flat fins which are angled with respect to the outer, longitudinal surface of the track, with the flat cleats making an acute angle with the surface of the track such that the cleats slant forward in a direction of travel of the track as the track is driven in its normal operation of propelling the power driven ski device forward. The cleats, slanting forwardly in the direction of travel of the track, dig downwardly into the snow to provide traction for the otherwise lightweight, power driven ski device. However, if such forward slanting cleats were used on a relatively heavy weight snowmobile, the track would quickly dig itself deeply into the snow and completely bog the snowmobile down.
3. Objectives
A principal objective of the invention is to provide a novel, resilient, flexible cleat which is readily attached to the outer surface of an endless traction belt or track used in driving snowmobiles, with the flexible cleat comprising a relatively narrow, elongate, essentially planar strip of resilient material which extends transversely across the track of the snowmobile and is oriented such that the planar strip slopes from the surface of the track at an acute angle in the opposite direction of the travel of the track as the track propels the snowmobile forwardly.
A particular objective of the present invention is to provide a plurality of such resilient, flexible cleats attached to and spaced about the length of the track of a snowmobile, whereby such track not only exhibits exceptional traction but also develops an unexpected lift which pulls the track and the snowmobile upwardly and over the surface of snow or even water when the snowmobile is being operated on such surface.
Another objective of the present invention is to provide inexpensive, resilient, flexible cleats which can be quickly and easily installed on essentially all conventional tracks used in propelling snowmobiles to increase the effective traction of such tracks and in addition to provide such tracks with a completely unexpected lift characteristic in combination with the increased traction.